Objective <p>To investigate the diagnostic delay in patients with psoriatic arthritis (PsA) attending dermatology and rheumatology clinics.</p> Methods <p>Two cohorts of patients with an established diagnosis of PsA from four dermatology clinics and two rheumatology clinics in Shanghai between February 2019 and January 2022 were retrospectively analyzed. Diagnostic delay was defined as the time from the onset of PsA-related musculoskeletal symptoms to PsA diagnosis. Diagnostic delay was compared by sex and arthritis type within each cohort. The cumulative diagnosis rates of PsA in both cohorts were also analyzed.</p> Results <p>The dermatology and rheumatology cohorts included 109 and 119 patients with PsA, respectively. The median diagnostic delay was significantly longer in the dermatology cohort than in the rheumatology cohort (median [IQR]: 45.5 [68.3] vs. 16.5 [25.6] months). Within each cohort, there were no significant differences in diagnostic delay between sexes. In the dermatology cohort, patients with pure axial PsA experienced a longer diagnostic delay than those with the peripheral type (median [IQR]: 57 [130] vs. 37 [66] months). Approximately 30% of PsA patients in the dermatology cohort had a diagnostic delay exceeding 6&#xa0;years. In contrast, in the rheumatology cohort, no patient with PsA experienced a diagnostic delay of more than 5&#xa0;years, with cumulative diagnosis rates of 39%, 58.5%, 84.8%, 96.7%, and 100% at &lt; 1&#xa0;year, &lt; 2&#xa0;years, &lt; 3&#xa0;years, &lt; 4&#xa0;years, and &lt; 5&#xa0;years, respectively.</p> Conclusion <p>Patients with PsA attending dermatology clinics experience significantly longer diagnostic delays compared to those attending rheumatology clinics.</p>